


The One with Gaster

by Antares10



Series: Banned-Together-Bingo-2020 fics [24]
Category: Undertale (Video Game)
Genre: Banned Together Bingo 2020, F/M, Family Drama, Found Family, Frisk and Gaster bonding, Grillby is a good friend, Implied Past Abuse, Implied Past Child Abuse, Mental Health problems, Non-Binary Frisk, Other, PTA Sans, Post-Undertale Pacifist Route, Prompt: Banned Language, Pta Sans au, Selective Mute Frisk, Sign Language, Undertale Monsters on the Surface, alternative universe, bonding over sign language, talk about past trauma
Language: English
Status: Completed
Published: 2021-02-07
Updated: 2021-02-07
Packaged: 2021-03-12 21:55:15
Rating: Teen And Up Audiences
Warnings: Creator Chose Not To Use Archive Warnings
Chapters: 1
Words: 3,124
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/29267580
Author URL: https://archiveofourown.org/users/Antares10/pseuds/Antares10
Summary: Written for the Banned Together Bingo 2020Gaster is back and everything is a bit to much for him. Luckily he meets a human child that not only is willing to help but also speaks his language.(Or: Things are broken but Gaster is motivated to put the pieces back together. He might need a little more help than he thought. Meanwhile Sans wants to move forwards and gets tested on his resolve like 5 seconds later)
Relationships: Frisk & Sans (Undertale), Frisk & W. D. Gaster, Grillby & Sans (Undertale), Sans/Toriel (Undertale), W. D. Gaster & Sans
Series: Banned-Together-Bingo-2020 fics [24]
Series URL: https://archiveofourown.org/series/1802935
Kudos: 14
Collections: Banned Together Bingo 2020





	The One with Gaster

**Author's Note:**

> This is Part of the PTA Sans universe and Part of "PTA Sans and other glorious things". Because I wrote it for the Banned Together Bingo, I put it as a one-short in here. You might want to check out the main-story, I would be happy about it ;)

Outside the void, it was... bright. Dark. Hot, cold, heavy, light, smooth and sharp and fast and slow and SO MANY THINGS AT ONCE.

Just laying on the ground had been a LOT and Gaster had a hard time dealing with it. He had a hard time dealing with the fact he COULD in fact deal or fail to deal or that he just could or couldn't anything.

Some things weren't quite right. Not yet. Memories were scattered all around. Time was still wonky. His soul just put itself together and parts of it had been stuck at really nasty places and times or just in the void which wasn't a place or time, but managed to be the worst of both.

It was all confusing and extra confusing that he could be confused.

Gaster was glad he didn't had to relearn to control a body. Apparently that knowledge came built-in, was integral enough in his soul to have carried over. It was still so overwhelming. Breathing was suddenly a very exciting task to do.

He looked at his hands again (his skeleton hands, he was a skeleton.. his arms and legs and body was all skeleton!) through the holes in his palms down to the ground under him. There was ground and air now, moisture in the air and wind and movement. There was LIFE.

He wanted to go home. That was the first, real thought he had. Go home.

_Go home._

It wasn't that easy however. Looking around the field he was sitting in, soft grass and earth and puddles of mud which slowly dried up in the sun... he was not quite sure where home even was anymore. Or WHAT his home was at this point. This was not the Underground but the Surface.

He had some vague memories or more like... access to information.

He knew that he was a monster. He knew monster and humans once were at war, the humans won, the monster got sealed away. He knew he was the royal scientist, tasked with finding a way to free monsterkind. He knew he failed. He knew he broke at least three promises and he knew he fell into the void. He knew that at some point, the monster were freed.

He remembered a sad and broken king and the sharp pull of pity. He remembered failing to find freedom but creating life instead. He remembered doing it again. He remembered loving his creations and he remembered a red haze and coldness and his hands locking up his sons and his hands creating a machine that would kill them and all the justifications he had told himself to make it right in his head, even if it wasn't.

He remembered agony and tears and deep deep deep regret.

He remembered missing a piece of himself and he remembered not caring and grieving at the same time.

Gaster put a hand to his head again, groaning.

A small skeleton, a child. Big round eyes, the spark of life. A soul that didn't turn out human but monster. The same face, smiling with trust and love and then it flickered and the same face was in pain and angry and full of fear and hate.

An other small skeleton, that was to young to really understand what happened, that always trusted him even after a part of him was lost and another part taking over on the most horrible way possible.

He used to be a FATHER. He used to have SONS, a family, a LIFE.

Gaster shuttered as more and more memories slotted into place.

He had HURT them.

He had hurt them and they were hurt and it was all his fault. His lost his sons, his family, his home ad his life. The void had swallowed him and shattered him and now he had put himself together. But what now? He had hurt them, how could he ever...

There was a hand on his shoulder.

Gaster flinched heavily, spinning around to see who or what touched him and almost fell over backwards again.

It was a human. A human child. They smiled at him and signed with their hands. Talking in Hands. Like him.

_Hello. Are you lost?_

Gaster could just nod dumbly.

_My name is Frisk. Do you want some help?_

Sans was feeling... better. Not great yet but better by a lot. Just a bit... restless. Heh, wasn't that a joke? But it was true.

Without the big project of getting Flowey a new soul he was left with a surprisingly big amount of free time at his hands. And now that he didn't need that time to panic or wait for something horrible to happen, he found himself.. .well... restless. A strange sensation where the pull to DO something without any idea for WHAT to do.

Toriel was teaching. Frisk was out with their friends. Papyrus was helping Undyne with something... so he was all alone at home. He could do some work but numbers and formulas just didn't seem to grab his attention in the moment. Not even his trombone inspired him today.

So after several minutes debating with himself and feeling restless and unsatisfied even with that, he finally got up and grabbed his jacket.

It was getting colder again. Summer slowly made way for fall and even with the warm weather during the last few weeks there was no denying the fact. Time moved on.

Sans looked at the colorful leaves all around him. Some birds were flying by way, way above him. All in all it was a nice day outside, just a bit chilly.

His feet were taking him to Grillby's without his input. He honestly only noticed where he had gone when the warm air coming from the door hit him. He was thinking of leaving right away again but Grillby had already noticed him, his gaze on Sans and his flames flickering with the beginning of a worry. So Sans changed his mind again and let his feet carry him to the counter and towards the fire elemental looking at him.

“Hey, Grills.” he greeted his friend as Grillby nodded at him.

“Hello, my friend...” he answered, softly. “What brings you in today?”

“My feet.” said Sans, winking before sitting down.

“Funny.” commented Grillby flatly.

“Kinda not.”, Sans mumbled. “They did kinda carry me here on their own.”

Grillby chuckled softly, amusement clear visible before his flames started to flicker with worry again. “Does something weight on your mind?”

“Not really...?”, said Sans. It was not a lie, he really... wasn't quite sure himself.

  
“Ah... you resolved your... philosophical problem?”

Sans hesitated.

“Not... really? I mean... I am still kinda thinking about it...?”

“The question if a person can change their way no matter how far along they have wandered on their chosen path?”

“Kinda, yeah.”, said Sans, sighing and slumping in on himself a bit. It's just him and Grillby here and talking to him had kept him sane during the very much not happy times of resets and helplessness... so he at least tried to give his confusing thoughts and emotions words.

“I keep thinking about the past a lot.” he confessed. “What happened and why and I... I thought about my...” dad, father, creator... “Former guardian a lot now.”

Grillby nodded at him slowly. Sans hadn't told him EVERYTHING about Gaster. But he had told him enough when he was young and scared and was suddenly alone with Papyrus with their former life having spectacular exploded in Hotland.

Sure, there was a time where Sans had taken care of Papyrus alone before, but back then Gaster had still taken care of them from afar, had kept his distance but was close by. Gaster had been still his FATHER back then and Sans had still believed him to be good and kind. He had been angry and betrayed but he had still trusted Gaster and he had still forgiven him and a part of him was HAPPY to have a little brother.

It was different after the machine. Gaster had hurt him and had planned on killing Papyrus. Gaster had trapped them and made him feel so helpless and hopeless and had taken any kind of control from him.

And then, after the fight, after the machine, Gaster was gone and most people didn't even remember. A lot of them even lost memories of him and Papyrus. It was lucky that the house in Snowdin was listed under Sans's name and most of the Snowdin inhabitants remembered the skeletons being around, even if they didn't remember Gaster and their connection to the royal scientist.

Grillby had remembered, just not everything. He remembered babysitting Sans and later Sans and Papyrus, he remembered that SOMETHING had happened and him having been angry at somebody and Sans needing support. He had asked Sans about it. Multiple times because whenever Sans tried to tell him about Gaster, he would have trouble recalling the conversation.

So Sans started trying to be vague enough so the new knowledge won't be erased but specific enough so Grillby would understand.

His former guardian was what he had settled on. He had told Grillby about... somebody that used to care for him and Papyrus, that betrayed their trust and hurt them but was now gone. Grillby knew that it was complicated, that Sans once loved this person and got burned badly by it. He knew that something went horrible wrong.

So Grillby's flames twitched a bit when Sans confessed to thinking about his past again, about his former guardian.

“... because of Azzy?”

“Yeah.” admitted Sans. “I mean... I know that my... former Guardian... probably was not in his right mind the last few times I saw him. But does that really excuse his actions?”

“... you were hurt.” said Grillby. “You are upset. But you wonder if there is something absolving the one who hurt you of guilt or responsibility.”

Sans nodded.

“And you wonder if you are required to forgive under changed circumstances.”

Sans nodded again. “I tried to forget the whole thing mostly... Papyrus doesn't remember anything about it. I uh... I kinda ranted at Asgore about it and I think he remembers a bit of my former guardian. He is a boss monster after all. But uh... other than this... if there is no harm, there is no fool, and all that?”

Grillby was silent for a while, thinking.

“... but you were hurt.” he finally said.

“uh... yeah, but...”

“You were hurt.” said Grillby again. “Somebody did it. Even if that somebody wasn't in their right mind... it really is similar to the Flowey problem, right?” he mused. “Harm was done. It wasn't harm done out of malice or well... let's say harm done by somebody being a victim in a way too. But still, harm was done. And it's entirely in your right to be upset and wanting comfort and security in harm not being done to you again.”

“He is gone.” mumbled Sans. “Gone from this plane and gone from the memory of most people.”

“That doesn't really matter.” said Grillby. “We are not talking about a punishment. We are talking about you feeling upset.”

Sans looked at Grillby again and sighed.

“... Do you want somebody to be punished?”, asked Grillby.

“Not really. I mean... Flowey... Flowey is gone and had his fair share of bad things happening to him. And my... former guardian...” Sans trailed off, trying to make sense of this himself. “... he already got punishment in a way?”

Grillby just looked at him and Sans finally shrugged.

“I mean... its not as if it would matter anyway... he is gone. I am... I am pretty fine. So it's fine.”

“... still...” said Grillby. “... I think it's important to acknowledge that you got hurt. That harm was done to you.” He paused for a moment, flames flickering, indicating a smile. “A person might not change at their core but good and bad decisions can be made at any time. For every bad there could be a good. But if you feel like punishment was had and your hurt got recognized the way you are satisfied with... it might be a start for moving on.”

“Moving on...” repeated Sans as if those words were new to them.

They weren't of course. He did move on. Moved on from his past, moved on from the resets, from the Underground.

Maybe he could be able to move on from Flowey and Gaster too.

He had Frisk and Toriel and Papyrus and all his friends. He was hurt in the past and now... he was better.

Living on the surface, starting a new life, new friendships and love and each moment following the next. Freedom to choose whatever he wanted. Getting into the PTA and in a way, understanding humans more and more.

And he WANTED this. He wanted and loved this life so much. It didn't really matter what Flowey did, it didn't really matter what Gaster did. It hurt, he'll remember, his pain got acknowledged. He was free.

The smile came easy and without Sans actually making himself smile.

“You are right, like always, Grills.” he said softly.

Gaster had to admit, this was a nice house. It looked... home-y.

Frisk had led him into the house all happily, signing out explanations and plans for their parents to meet him, for dinner together and showing him more of the neighborhood and the town later, while they were helping him to sit down on the soft soft couch.

It was a well-loved couch, some spots looked a bit rough like there had been spilled drinks that were scrubbed out and there was a small black spot half hidden behind a pillow that looked like an accident with a permanent marker. The pillows were all different in size and shape and color but they still fit together well and the blanket Frisk gave Gaster just a moment later was nice and warm and fluffy and smelled like sweet tea.

The living room felt just as the couch: soft and warm and lived in and well loved. There was a fireplace not far from him, cold in the moment, but over it were lots of pictures of a happy family. There were hand-painted pictures of the walls too, probably made by a child. There were flowers on the small table in front of him, golden flowers blooming and shimmering in the sunlight coming from the window. The TV was dark and silent in front of him. The carpet under his feet was soft and clean and of a creme color. There were shelves of books and another shelf with lots of knick-knacks, vases and small artwork and postcards and other stuff.

He was sitting in the middle of some family's life, all the while a human child talked in hands to him.

_**How did you learn to talk in hands?** _ Gaster finally asked, interrupting the human.

_My voice doesn't always work, so they taught me so I could talk when I can't talk._ The human (Frisk, they said their name was Frisk) answered. _Mom taught me more when she adopted me. I am still learning but I am really good now, even dad says so!_

Gaster blinked at that. He knew most monster could understand hands but humans? No human he heard of was talking in hands.

_**I didn't know humans knew hands.** _

_It's called different here._ Frisk answered. _But there are lots of different hand languages. Most humans don't need it and don't learn it. But there are still many that do and can._

Gaster nodded at that slowly, eyes wandering again when he noticed one particular picture.

Most of the photos in the room were of a tall goat monster (Asgore? … no, it's a female one... is... is that the missing Queen of the monster? Toriel? Gaster couldn't remember if he ever met her, his memories were still all messed up) and Frisk, as well as a fish-monster, a lizzard monster and there were some of Asgore too (Gaster would recognize him everywhere) and a tall skeleton monster that looked kinda familiar... but one of the pictures showed a smaller skeleton, more stocky with a round skull and a wide smile and Gaster felt as if the void just opened up under him again.

That... that skeleton. That small skeleton. That was Sans.

It was Sans, the son he hurt, he hurt so so much and he was so sorry. So very very sorry. And there was a picture of his son on the wall and he looked so happy on it.

_**Frisk?** _ Gaster asked. **_Frisk, this picture... this skeleton... how do you know him?_ **

_Huh? Oh, Sans?_ Said Frisk. Gaster nodded. _He is my dad... well... dunkel of course!_

Frisk was giggling but Gaster felt ice cold dread. Frisk was his son's child? Well they said they were adopted... oh dear.

_**Frisk? Where is your... father? Maybe I really shouldn't I be here. Maybe I should just go and...** _

And just in that moment the door opend and Sans, his son, was walking in.

He looked... he looked good. He was smiling, his stance was relaxed and what Gaster could feel of his magic from this far away, he was totally at ease. And then he saw him and he shifted, eye glowing bright blue as Frisk was yanked away from Gaster by a sheen of blue magic and behind the skeleton (he was protecting them, tried to protect his family, because Gaster had hurt him and his brother already so badly but still, it hurt!) and suddenly the room grew colder and darker, as if the sunlight and warmth just faded away.

And Sans was looking at him just as coldly, ready to fight and protect and determined to stand his ground, magic in the air all around him and Gaster felt like crying all over again.

“What. Are you. Doing here?”, asked Sans, voice cold and hollow and Gaster found himself unable to even lift his hands to answer because what COULD he even say?

“Dad...”

A tiny voice came from the human, small and raspy and suddenly the cold and the magic was gone because Sans had turned to the human. His blue eye was still on Gaster, a clear warning, but was still still giving the small human his full attention (his child, Frisk was his child!)

“He's Gaster.” said Frisk softly, their voice barely audible to Gaster. “He is lost and needs help. He is my new friend.”

The small look Sans was giving him could have frozen a small lake. Gaster felt himself sinking more into the couch.

This... this could have gone way better.

**Author's Note:**

> This chapter (the one with Gaster) was written for the Banned Together Bingo 2020 prompt: Banned Language.
> 
> I kinda wanted to show Frisk and Gaster bounding a bit over both of them talking in hands. Did you know that sign language is banned in certain parts of the world? Or that some people actively try to prevent people using it??? Also remember the start of the PTA AU where we all were convinced Linda would pull the "silent hands" thing (which is super bad like never do that!) on kids like Frisk?  
> So yeah, I used that prompt for this chapter too.  
> The Banned Together Bingo was a lot of fun to do and I KNEW that I would write a PTA Sans AU chapter for it too, just to give my butt the needed to kick to get back into the writing game XD This chapter was outlined and the first scene written in march 2020 during the first lockdown of my country but sadly I got busy and lost a bit of motivation over the year. But I picked it up again in December and FINALLY finished it. So here it is, I hope you all enjoyed it. XD


End file.
